<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
	<style type="text/css">
		*{
			margin: 0;
			padding: 0;
		}
		div{
			width: 400px;
			height: 200px;
			background-color: white;
			margin: 50px;
			padding: 20px;
			border: 5px solid #f5f5f5;
			border-radius: 5px;
			box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.3);
		}
		.one{
			margin: 5px 20px 20px 20px;
		}
		.two{
			margin: 10px;
		}
	</style>
</head>
<body>

	<div>
		<h2 class="one">工具</h2>
		<h3 class="two">在线转换器</h3>
		<h3 class="two">参考设计库</h3>
		<h3 class="two">Scheme It</h3>
		<h3 class="two">对照检索</h3>


	</div>


</body>
</html>